You are correct— Einstein was no economist.
Einstein was however the "Public Enemy #1" of Nazi Germany.
(source: time.com/Einstein-England)

It sort of throws a wrench in the whole Nazi="real socialists" thing. :)
I think he wrote the essay partially to vent against Christianity, since he had lost many friends in the Holocaust, and Nazi Germany was 97.5% Christian (according to the official 1939 census— goog "Nazi religion" and the wikipedia article has the breakdown there.)

Anyways— I'm glad you liked the essay.  It is sad that Communism effectively turned into a religion. At least the Nordic model (which combines capitalism and socialism) seems to be the best economic system out there. I think that is what Germany uses now, too.  To their credit— they learned from their mistakes. Also; they are no longer 97% Christian, but rather about 51%. Angela Merkel was educated at Karl Marx university, learned Quantum Chemistry before she became Chancellor. Smart as a razor!